Some undersea hydrocarbon reservoirs contain a high proportion of heavy crude oil (hydrocarbons), so output from the reservoir (over a period of a plurality of days) comprises over 50% hydrocarbons of a density above that of water and with a high viscosity. Such heavy crude oil generally contains at least 60 carbon atoms per molecule and/or has a viscosity on the order of magnitude of over 0.5 poise. Other liquid hydrocarbons (light oil or light liquid hydrocarbons) generally have about 5 to 10 carbon atom per molecule (light oil). Hydrocarbons with less than 4 or 5 carbon atoms per molecule are generally gas. Heavy oil hydrocarbons are difficult to treat and are difficult to pump into and out of storage tanks. The heavy crude can be cracked in refineries to produce light oil (generally oil having a specific gravity less than water and with a low viscosity) which is usually the most desirable hydrocarbons, but considerable effort is required to handle and transport the heavy crude to the refinery. A system that could be used at an offshore heavy crude oil production facility to crack heavy crude oil so as to facilitate its transport and transfer through pipes to a further refining and treatment facility, would be of value.